1. Field of the Invention
The present invention relates to a novel hydroquinone derivative useful for treating various allergic diseases and a pharmaceutical use thereof. More particularly, the present invention relates to a therapeutic agent for allergic diseases which contains the hydroquinone derivative as an active ingredient.
2. Description of the Prior Art
Allergic reactions which cause allergic diseases are generally classified into types I to IV. Particularly, the type IV reaction has been known to be dominant in atopic dermatitis, contact dermatitis, chronic bronchial asthma, psoriasis, graft-versus-host diseases, and so on. Effectiveness of antihistaminics and chemical mediator release inhibitors against these diseases is limited, and therefore steroids have been used for their therapy. In addition, cyclosporin and taclorims have also been known to be effective for suppression of graft rejection and therapy for graft-versus-host diseases developed after transplantation, and their application has been expanded into therapy for dermatitis Lancet, 339, 1120 (1992); J. Invest. Dermatol, 98, 851 (1992), etc.!. However, such drugs are sometimes disadvantageous. Steroids cause undesirable side effects such as infectious diseases, atrophy of adrenal glands, osteoporosis, diabetes mellitus, and growth inhibition in children. For cyclosporin or taclorims, side effects caused by their immunosuppression effect, such as infectious diseases and diabetes mellitus, would be feared.
The applicant have proposed uracil derivatives which can inhibit type IV allergic reactions (see Japanese Patent Application Laid-open No. 8-109171 which corresponds to EP700908A1). However, development of more potent and safe drugs for treating allergic diseases, especially those responsible for type IV allergic reactions, is still required.